1. Field of the Invention
The present invention relates to a motor control system. More specifically, the present invention relates to a motor control system which is utilized for controlling a drum motor and a capstan motor of a VTR, for example.
2. Description of the Prior Art
With referring to FIG. 9, in a conventional motor control system 1, speed error data is outputted by a speed detection portion 3 on the basis of a speed signal (FG signal) from a motor 2, and phase error data is outputted by a phase detection portion 4 on the basis of a phase signal (PG signal) from the motor 2 and a vertical synchronization signal (Vsync). Then, the speed error data and the phase error data are synthesized with each other, and a synthesized result is inputted to a driver 6 via a filter 5, such that the motor 2 is driven by the driver 6.
With referring to FIG. 10, in another conventional motor control system 1', the speed error data is outputted by the speed detection portion 3 on the basis of the FG signal, and speed integration data is outputted by a speed integration portion 7 by sequentially adding differences between the speed error data and a theoretical FG period data that is applied from an outside. In a reproducing (play) mode, the speed integration data is synthesized with the speed error data, and a synthesized result is given to the driver 6 through the filter 5. In a recording mode, the above described theoretical FG period data and phase difference data between the PG signal that is applied via a switch 8 and the vertical synchronization signal Vsync are synthesized with each other, whereby the phase lock between the vertical synchronization signal Vsync and the PG signal can be established by changing the theoretical FG period data.
In the conventional motor control system 1 shown in FIG. 9, it is impossible to secure a sufficient pull-in range for the phase. In contrast, in the motor control system 1' shown in FIG. 10, the pull-in range can be made broader enough because an integration type phase servo-control is performed; however, in the both prior arts, there was a problem that a sufficient gain can not be secured in a case of a miniaturized motor which is utilized in an 8 mm VTR, for example, as shown by a line B in FIG. 4. In addition, a line C in FIG. 4 is representative of a transfer function of a case where only a speed servo-control is performed.